Considerazioni su variazioni climatiche e disponibilità idriche in alcune località dell'Italia centrale

Abstract

Twentieth century rainfall and temperature data from Cortona, Terni and Perugia (central Italy) indicate a regional tendency to an increase in temperature and a decrease of rainfall. By extrapolating present pluviometrie and thermic trends the mean monthly water excess in these sites for the years 2020/2030 and 2040/2050 has been estimated. The mean monthly flow of the Acquina river (near Perugia), taken as a sample basin, is estimated by means of a model. Increase in evaporation from free surfaces is modest, reaching values of a few percent. Despite this result, the study forecasts a 30% decrease in water availability for the next decades. This result is based on the hypothesis that current dry climatic condition in the area between Cortona and Terni continues. Although this conclusion is uncertain, it is worth mentioning that most Global Climatic Models are in agreement - qualitatively, at least - with the above result. Further studies on the subject are needed to obtain improved forecasts.